A defendant visits the office of a plaintiff's lawyer and "served" a copy of the petition. The defendant signs an "acknowledgment of service" that reads, "Due and legal service of process is hereby acknowledged." Process had yet to issue and was, therefore, not, in fact, attached. Defendant doesn't know that to avert default judgment he must answer the petition. He doesn't answer and does lose by default. He later claims insufficiency of process on the grounds that no "process" was served with the petition.